March 2023 Summaries

Determinate Systems aims to simplify the use of Nix, a powerful package manager traditionally associated with Linux, by making it equally accessible on macOS. To achieve this, they have developed a sophisticated continuous integration (CI) setup using Buildkite, which addresses the limitations of GitHub Actions, especially in supporting macOS, including Apple Silicon. Their unique CI infrastructure comprises four physical Macs located in the CEO's basement, configured with Nix and managed remotely via Mosyle, allowing each machine to be reset and reconfigured for every Buildkite job. This setup not only provides cost benefits compared to cloud-based solutions like AWS, which are expensive due to Apple's licensing restrictions, but also ensures speed and ephemerality, with each job cycle taking only 5-7 minutes. By leveraging Buildkite's ability to delegate tasks efficiently, Determinate Systems can maintain a high level of determinacy in their systems, crucial for their mission to enhance the usability of Nix on macOS.

Determinate Systems is working on making Nix, an extremely powerful but often tricky language, build tool, and package manager, easier to use for everyone, including macOS users. The company uses Buildkite's unique feature set to achieve this goal. While GitHub Actions is used for straightforward CI logic, Buildkite is employed when needs go beyond what Actions can offer. One area where GitHub Actions does not shine is in support for macOS machines, particularly Apple Silicon runners. Determinate Systems has built an internal tool called bonk that erases the machines and shuts them down using the Mosyle API, making each Buildkite job run on a “fresh” machine. The company's setup of ephemeral macOS machines has been hugely beneficial, providing cost savings compared to cloud-based solutions and faster turnaround times for CI jobs.